Parity Rebuild Confusement

[NoobSpy]

Hi Guys,

 

Maybe someone can help me with this and is willing to explain how this works.

My original parity drive had some bad sectors and I decided to replace it and while I was at it upgrade it and my server. I found a good deal with some minimal used drives someone bought from a bankruptcy.

 

What did I do:

1. I removed the old parity drive
2. Zero-ed the new drive
3. Installed the new larger drive and UNRIAD prompted to rebuild the parity and started to do it's thing

 

Now the strange thing:

UNRAID showed the progress up to 0.3% and then the info on the bottom left disappeared. It didn't show any progress up until about 37% except that it was showing the time it ran. At it 37,1% I could see that it was writing the parity. It continued and finished without any problem.

 

But the weirdest thing is that the other data-drives were spun down most of the time.

 

How did it make the parity? Do I need to check it again by doing a parity check? But that will take another 2 days.

How does this process work?

 

[itimpi]

What are the sizes of your data drive and the parity drive?  Once the parity build has gone past the size of a data drive then that data drive can be spun down as it is no longer needed.

[NoobSpy]

My old parity drive was 8TB is now 14TB (I have 3 more to install/upgrade)

The data drives are: 2x 8TB and 2x 4TB.

 

One additional question. Is it better to just add the new drive(s) to the pool one by one and just copy the data over and remove the old drive?

[itimpi]

1 minute ago, NoobSpy said:

One additional question. Is it better to just add the new drive(s) to the pool one by one and just copy the data over and remove the old drive?

It would be easiest to simply replace each drive in turn to a larger one and let Unraid rebuild its data.   In each case you will have the removed drive available with its data intact until you are confident that the rebuilt has been successful.

[Frank1940]

3 minutes ago, NoobSpy said:

Is it better to just add the new drive(s) to the pool one by one and just copy the data over and remove the old drive?

 

Do you need more space than replacement with a larger drive would achieve? 

 

Is there any problem with the present drive that indicate that is might fail soon?  (Old age is not a qualifier here!!!--Unless that drive is more than six years old.)

 

Do you have room in the case for another drive?

 

Depending on the answer to these questions, (1) you might just leave the old drive in the array until it actually has a problem.  Install the new drive and use its full capacity for additional files.  When it fails, then replace it with a new drive.   (2) If there is not room for a new drive, then replace it. You may be removing a drive that still has several more years of service left in it but that might be preferable to a new case. 

 

In any case, the LAST thing I would recommend doing is to copy the data over just so you can remove the drive.  Always remove the old drive and let Unraid rebuilt the data on the new drive as @itimpi suggested.  It is faster (after you do the copy and remove the old drive, you then have to do a parity rebuild)  and less prone to cockpit error!

[NoobSpy]

55 minutes ago, Frank1940 said:

 

Do you need more space than replacement with a larger drive would achieve? 

 

Is there any problem with the present drive that indicate that is might fail soon?  (Old age is not a qualifier here!!!--Unless that drive is more than six years old.)

 

Do you have room in the case for another drive?

 

Depending on the answer to these questions, (1) you might just leave the old drive in the array until it actually has a problem.  Install the new drive and use its full capacity for additional files.  When it fails, then replace it with a new drive.   (2) If there is not room for a new drive, then replace it. You may be removing a drive that still has several more years of service left in it but that might be preferable to a new case. 

 

In any case, the LAST thing I would recommend doing is to copy the data over just so you can remove the drive.  Always remove the old drive and let Unraid rebuilt the data on the new drive as @itimpi suggested.  It is faster (after you do the copy and remove the old drive, you then have to do a parity rebuild)  and less prone to cockpit error!

 

The drives are full and have space varying from 63GB to 125 and have 46296 power on hours. There are no errors.

It was an upgrade I postponed as long as possible.

 

Thank you so much guys.

[Frank1940]

1 hour ago, NoobSpy said:

The drives are full and have space varying from 63GB to 125 and have 46296 power on hours. There are no errors.

It was an upgrade I postponed as long as possible.

 

 

One more thought.  With that age of drive and apparently all of your drives have the same number of hours on them, With what  the file system that the drives are formatted?   If it is reiserfs, you should consider change to XFS or btrfs.  (The developer of reiserfs has been in prison since about 2010 serving a life sentence for murder.  The structure is hopelessly outdated for current drive sizes and, often, has performance issues as the drive fills up.)   Here is a link to the thread for doing the conversion:

 

     https://forums.unraid.net/topic/54769-format-xfs-on-replacement-drive-convert-from-rfs-to-xfs/#comment-535203

 

I have done it for two servers and it is hassle of the first magnitude.  But since you were already considering doing something quite similar, it is a way to kill two birds with one stone.